Re: 2.4 vm, program load, page faulting, ...

wind
2003-03-17T19:22:11Z

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On Mon, Mar 17, 2003 at 08:06:36PM +0100, wind-lkml@cocodriloo.com wrote:
> On Mon, Mar 17, 2003 at 07:57:49PM +0100, Marc-Christian Petersen wrote:
> > On Monday 17 March 2003 18:38, wind-lkml@cocodriloo.com wrote:
> >
> > Hi Wind,
> >
> > > > I wonder if this could be done by walking and faulting
> > > > all pages at fs/binfmt_elf.c::elf_map just after do_mmap...
> > > > will try it just now :)
> > >
> > > OK, this is not tested, since I'm compiling it now... feel free
> > > to correct :)
> >
> > mm/mmap.c:
> >
> > unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, unsigned
> > long len,
> > unsigned long prot, unsigned long flags, unsigned long pgoff)
> > {
> >
> > your "do_mmap_pgoff" calls 7 arguments. Obviously it cannot compile 8-)
> >
>
> My first patch, I'm just becoming intimate with printk ;)

OK, so I took a different approach, and just called handle_mm_fault just
like if there had been user-level accesses to the file.

Applied on 2.5.63-uml1 and booted debian woody with it.

Can any of you try it on a real machine? (I dont have a test machine :(

Greets, Antonio.

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--- orig/fs/binfmt_elf.c Mon Mar 17 20:30:17 2003
+++ work/fs/binfmt_elf.c Mon Mar 17 20:30:29 2003
@@ -259,12 +259,26 @@ create_elf_tables(struct linux_binprm *b
static inline unsigned long
elf_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type)
{
- unsigned long map_addr;
+ struct mm_struct *mm;
+ struct vm_area_struct *vma;
+ unsigned long map_addr, n;

down_write(&current->mm->mmap_sem);
map_addr = do_mmap(filep, ELF_PAGESTART(addr),
eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr), prot, type,
eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr));
+
+
+ addr = ELF_PAGESTART(addr);
+ mm = current->mm;
+ vma = find_vma(mm, addr);
+ if(!vma)
+ goto out;
+
+ for(n = 0; n < eppnt->p_filesz; n+=PAGE_SIZE)
+ handle_mm_fault(mm, vma, addr + n, 0);
+
+out:
up_write(&current->mm->mmap_sem);
return(map_addr);
}